The present invention relates to rock crushing machinery generally, and more particularly to jaw type rock crushing machinery wherein crushing forces are developed between two jaws, one a stationary jaw and the other a movable swing jaw.
Large rock crushing machinery is typically used in remote areas where operating problems must be handled on site. It is therefore a desirable object to design and construct a rock crushing machine which can be maintained and serviced by field operators in the minimum amount of time with a minimum amount of effort and skill. It is also important that any maintenance procedures that are required be carried out with minimal risk to the operator's safety.
One of the major problems encountered during rock crushing operations is the introduction into the crusher of non-crushable material, such as tramp iron. Such a non-crushable material causes the crusher to stall and can introduce serious structural problems. To avoid structural problems the flywheel of the crusher is designed to release when a non-crushable material enters the crushing chamber, thereby disabling the crusher until the material is removed. In a conventional jaw type rock crusher, removal of the non-crushable requires extensive downtime and expenditure of many labor hours, a process which lowers productivity, increases costs and affects operator safety.
The present invention provides a hydraulic jam release system which greatly simplifies the removal of non-crushables from a rock crusher and which substantially reduces the downtime involved in the removal operation. By means of the present invention, the massive steel stationary jaw of the rock crusher, which typically encounters crushing forces in excess of 200,000 pounds, depending on applied housepower, crusher r.p.m. and swing jaw displacement, can be retracted hydraulically and then hydraulically returned to its operative position. The invention provides easy-to-use hydraulic controls whereby a field operator can easily and efficiently unjam a crusher apparatus and return it quickly to service. Moreover, the jam release system of the invention provides for total mechanical isolation of the release system's hydraulics from the stationary jaw thereby allowing the hydraulic system to remain depressurized during the normal operation of the jaw crusher.